Wolf was still trying to get over Nick pulling Eisen's doorknob off with ease when the insults began flying. In his position behind Nick and off to the side, he could see both Eisen's and Rory's shocked faces, and he could make out what they were saying. Since Wolf was very good at figuring things out by context, he was also able to take a wild guess at what Nick was, undoubtedly, shouting at the two men.
There had been a little conflict within him upon first finding out Eisen had cheated with a man. It didn't change the fact that Eisen had cheated and hurt his cousin, but so many gay (or bisexual or whateversexual) men and women were too scared to come out of the closet because of society's reaction. They tried to live hetero lives that ultimately didn't work because they couldn't change who they were, and so if Eisen had been sleeping with men (Rory) on the side because of his fear of coming out but need of sex he enjoyed, Wolf could find a little sympathy in his heart for the dumbass.
However, when he got into Eisen's apartment and saw him and Rory together, read what Rory said about Nick not knowing real love, and how Eisen was speaking for Lexie trying to get Nick to back down (even if what Eisen was saying was true), Wolf was glad Nick was there to beat the shit out of them. Or, rather, Eisen. Rory got a free pass because of his leg situation.
He stood back and watched Nick wail on Eisen almost idly, looking bored despite the tension in the room. Wolf was pissed off, sure, but he didn't really see it as his fight. If no one else had been willing to step up and take it he would have lead, but Nick wanted to be the payback, and Wolf knew he had to keep an objective (as much as possible, anyway) eye on the whole situation.
Around the time Rory started yelling, Wolf began to blink rapidly. What he couldn't hear created strange colored waves in his mind's eye, but this time they began to bleed out into reality. So faintly, he could see Rory's words as ribbons of light heading toward Nick and Eisen, but they were gone by the time Wolf's eyes rested on the pair again.
"Hey," he called, his voice loud by default, but if he'd been able to communicate tone properly the word would have come out unsure. "Nick, might want to wrap it up. Someone's going to hear and call the cops." Despite all of the joking about jail that had gone on, Wolf really wanted to avoid that.